The present invention relates to a semiconductor device and, more particularly, to a semiconductor device having a mounting member with which a functional device, such as a power module, is mounted on a cooling member.
In recent years, a hybrid vehicle provided with a drive-force source composed of an engine, such as an internal combustion engine, and a motor such as an electric motor, have been widely spread in use. Such a hybrid vehicle has a power drive unit through which a direct current, supplied from a battery, is converted to an alternate current for supply to the motor whereas an alternate current, resulting from regenerative operation of the motor, is converted to a direct current for storage in the battery.
The power drive unit is provided with a power module for performing such DC/AC conversion and AC/DC conversion. Such a power drive unit employs a relatively large current and, hence, a power module, incorporating so-called power semiconductor elements, is assembled therein. That is, as the power modules operate, a relatively large amount of heat is generated. To ensure a heat radiation path, therefore, a heat sink is attached to the power module.
Japanese Patent Application Laid-Open Publication No. 2009-158631 discloses a power drive unit having a power module pressed against a heat sink and fixedly secured thereto upon using a pressing member. In such a structure, the spring member, formed in a nearly circular shape, is interleaved between the power module and the pressing member with a view to causing the power module to be fixedly secured onto the heat sink for avoiding limitations in layout and a decrease in heat radiating performance.
Further, Japanese Patent Application Laid-Open Publication No. 2009-158632 discloses a power drive unit having a plurality of power modules pressed against a heat sink and fixedly secured thereto upon using pressing members. In such a structure, a spring member is interleaved between each of the plurality of power modules and the pressing member with a view to causing the power module to be fixedly secured onto the heat sink for avoiding limitations in layout and a decrease in heat radiating performance, while equalizing load applied to the plurality of power modules.